New offers today (claim by 24 Aug):
Save an Extra 50% on Back-to-School Groceries at Amazon.com -- expires 24 Sep
Buy a Business or Investing Book for $1 -- expires 24 Sep
The first one is 50% off an order, not an item, you can save hundreds $$ (I did). Can layer on individual promo codes from items (nearly every item I purchased had 5%-15% off) and coupon codes (Amazon gives these out randomly, but I hit on four of them with my order).
Both offers are one per device.